A Contra Costa property tax appeals board has agreed to postpone for up to two years Chevron’s 2010-11 challenges of the taxable worth assigned to its Richmond refinery.

It’s the latest move in Chevron’s eight-year fight with county Assessor Gus Kramer over the taxable value of its large Richmond refinery complex.

Chevron sought the 2014 delay to await the outcome of pending lawsuits in Superior Court, company spokesman Dean O’Hair said.

The company is suing the Contra Costa Assessment Appeals Board’s decision on its 2004-06 appeal. The refinery sought a $73 million tax refund but was awarded $17 million.

Chevron filed the second lawsuit last July in its ongoing dispute with the appeals board and Kramer over a complex procedural matter.

The company may also take the county to court over the appeals board’s latest decision on the refinery’s 2007-09 tax challenge. The panel rejected Chevron’s argument that it was due a $73 million refund out of its $129.5 million tax bill for the three-year period and ruled that the company instead owed an additional $27 million.

In the 2010-11 appeal, the petroleum giant seeks to cut by nearly half the $65 million in property taxes it paid during the two-year period, asserting that Kramer again overvalued the refinery.

Chevron is also closely watching the outcome of a case brought by the Western States Petroleum Association against the state Board of Equalization.

A Southern California appeals court in January tossed out a 5-year-old state regulation — dubbed Rule 474 — that determined how to set the taxable value of oil refineries. The rule limited the extent to which the declining value of aging equipment could reduce a refinery’s overall tax bill.

Dumping the rule favors the state’s 13 oil refineries, most of all Chevron, the county’s biggest taxpayer.

The Board of Equalization is seeking a California Supreme Court review of the lower court’s decision.